It has been discovered that the medical outcome for a patient suffering from severe brain trauma or from ischemia caused by stroke or heart attack or cardiac arrest is improved if the patient is cooled below normal body temperature (37° C.). Furthermore, it is also accepted that for such patients, it is important to prevent hyperthermia (fever) even if it is decided not to induce hypothermia. Moreover, in certain applications such as post-CABG surgery, it might be desirable to rewarm a hypothermic patient.
As recognized by the present invention, the above-mentioned advantages in regulating temperature can be realized by cooling or heating the patient's entire body. Moreover, the present invention understands that since many patients already are intubated with central venous catheters for other clinically approved purposes anyway such as drug delivery and blood monitoring, providing a central venous catheter that can also cool or heat the blood requires no additional surgical procedures for those patients. The following U.S. patents, all of which are incorporated herein by reference, disclose various intravascular catheters/systems/methods: U.S. Pat. Nos. 6,749,625, 6,786,916, 6,581,403, 6,454,792, 6,436,130, 6,146,411, 6,109,783, 6,419,643, 6,416,533, 6,409,747, 6,405,080, 6,393,320, 6,368,304, 6,338,727, 6,299,599, 6,290,717, 6,287,326, 6,165,207, 6,149,670, 6,146,411, 6,126,684, 6,306,161, 6,264,679, 6,231,594, 6,149,676, 6,149,673, 6,110,168, 5,989,238, 5,879,329, 5,837,003, 6,383,210, 6,379,378, 6,364,899, 6,325,818, 6,312,452, 6,261,312, 6,254,626, 6,251,130, 6,251,129, 6,245,095, 6,238,428, 6,235,048, 6,231,595, 6,224,624, 6,149,677, 6,096,068, 6,042,559, and U.S. patent application Ser. No. 10/355,776. Less optimally, surface cooling can be used. U.S. Pat. Nos. 6,827,728, 6,818,012, 6,802,855, 6,799,063, 6,764,391, 6,692,518, 6,669,715, 6,660,027, 6,648,905, 6,645,232, 6,620,187, 6,461,379, 6,375,674, 6,197,045, and 6,188,930 (collectively, “the external pad patents”), all of which are incorporated herein by reference, disclose such surface cooling systems. In both intravascular catheters and external pad systems, coolant such as a gas or saline is circulated through the heat exchange element.
Regardless of the particular heat exchange element that is engaged with the patient, as understood herein it may be advantageous to use such a system during surgical procedures to control patient temperature. As further understood herein, some procedures may employ another component such as a heart-lung machine (HLM) that can also function to control patient temperature. The present invention understands that during such procedures, a primary temperature control system such as those disclosed in the above patents can be used to assist the other component, e.g., the HLM, in reducing patient temperature to a very low level. However, as further recognized herein it is important to avoid the control processor of one system from “fighting” the control processor of the other system during such assist procedures.